JP2016042075A - Systems and methods for determining position of transmitter of bistatic radar system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine a position of a transmitter in a bistatic radar system.SOLUTION: A bistatic radar system 100 may include: a transmitter 102; a target 106 at a first known position 110; a receiver 104 at a second known position 108; and a transmitter position determination unit. The receiver 104 is configured to receive one or more reflected radar signals transmitted from the transmitter 102 and reflected off the target 106. The receiver 104 is configured to receive one or more direct radar signals transmitted from the transmitter 102. The transmitter position determination unit is configured to determine a position of the transmitter 102 on the basis of a determination of a distance between the first and second known positions and a determination of a first angular difference θ1 between the reflected radar signal(s) and the direct radar signal(s) that are received by the receiver 104.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present disclosure generally relate to radar systems and methods.

  Radio radar systems typically use radio waves to identify the distance, altitude, direction and / or velocity of an object. Radar systems can be used to detect aircraft, ships, vehicles, guided missiles, weather, terrain, and the like. Radar transmitters or illuminators typically include antennas that transmit radio or microwave pulses that encounter and reflect an object. Part of the energy of the reflected wave is received by the antenna of the radar receiver.

  In a monostatic radar system, the transmitter and receiver are located at the same location (ie, juxtaposed). In contrast, a bistatic radar system includes transmitters and receivers that are in separate and separate locations. For example, the transmitter and receiver of a bistatic radar system may be hundreds of miles apart.

  In order for a bistatic radar system to work, the position of both the transmitter and the receiver need to be known, whether they are moving or not. For example, in aviation applications, if both the transmitter and receiver are moving (such as when on board an aircraft), the location of both the transmitter and receiver are frequently updated. Once the transmitter and receiver locations are known, the location of unknown targets within the radar system can be determined.

  As can be appreciated, in order for known bistatic radar systems to function properly, the transmitter and receiver communicate with each other or with a remote control center to provide location information. Thus, the transmitter and receiver cooperate with each other in such known bistatic radar systems. However, providing a communication system between a transmitter and a receiver increases the cost and complexity of the radar system. Furthermore, if the communication system fails or does not operate, the entire radar system also does not operate.

  In addition, if the transmitter and receiver are controlled by independent and separate organizations, the system may not be able to work. For example, a radar transmitter may be mounted on an aircraft controlled by a first organization, such as a government, while a radar receiver may or may not be cooperative or friendly with the first organization. It can be mounted on an aircraft that is controlled or owned by a separate, independent organization. In such a scenario, the transmitter may not communicate with the receiver, thereby preventing the receiver from utilizing a bistatic radar system that includes the transmitter.

  Some embodiments of the present disclosure include a transmitter in an unknown position at a first stage, a target in a first known position, a receiver in a second known position, and a transmitter locating unit. A bistatic radar system that can be included is provided. The receiver receives (a) one or more reflected radar signals transmitted from the transmitter and reflected from the target, and (b) one or more orthogonal radar signals transmitted from the transmitter. Composed. A transmitter location unit determines the distance between the first and second known locations and between one or more reflected radar signals and one or more orthogonal radar signals received by the receiver. Based on the identification of the first angular difference, the transmitter is configured to identify a position. Each of the transmitter and target may be moved in position or may be fixed.

  In at least one embodiment, the transmitter stops communicating the location of the transmitter. In at least one embodiment, the receiver includes a transmitter location unit.

The first time (T ₁ ) at which the reflected radar signal (s) or direct radar signal (s) is received by the receiver and the other of the reflected radar signal (s) or direct radar signal (s) By measuring the time difference between a _second time (T ₂ ) one is received by the receiver, the transmitter location unit can be configured to identify a bistatic distance difference. The transmitter location unit may be configured to convert the time difference into a bistatic distance difference by multiplying the time difference by the speed of light.

Assume that the transmitter is separated from the target by a _first linear distance (S ₁ ). Let the target be separated from the receiver by a _second linear distance (S ₂ ). Assume that the receiver is separated from the transmitter by a _third linear distance (S ₃ ). The transmitter location unit sets the first distance, the second distance, and the third distance to the first time and the second time, and S ₁ + S ₂ −S ₃ = C * (T ₁ −T ₂ ). (Where C is the speed of light) and can be configured to relate. The transmitter location unit may be configured to identify K = S ₁ -S ₃ as K = C * (T ₁ -T ₂ ) -S ₂ . The transmitter location unit may be configured to identify the third distance as S ₃ = (S 2 ² −K ² ) / (2S ₂ cos θ ₁ + 2K). Certain third distance S ₃ is, gives the position of the transmitter.

  In at least one embodiment, the transmitter localization unit identifies a second angular difference between the main beam transmitted from the transmitter toward the target and the side lobe transmitted from the transmitter toward the receiver. Can be configured to. A transmitter location unit may use the second angular difference to determine the accuracy of the transmitter's particular location.

  The transmitter location unit may also be configured to identify one or both of a first height of the transmitter relative to the receiver or a second height of the target relative to the receiver.

  Some embodiments of the present disclosure provide target location data indicative of a first location of a target to a transmitter location unit, and receiver location data indicative of a second location of a receiver. Providing to the unit, receiving one or more reflected radar signals transmitted from the transmitter and reflected from the target at the receiver, receiving one or more orthogonal radar signals transmitted from the transmitter at the receiver And a transmitter based on the distance between the first position and the second position and the first angular difference between the reflected radar signal (s) and the direct radar signal (s) A bistatic radar method is provided that may include identifying a third location of the transmitter with a location unit.

  Some embodiments of the present disclosure identify the distance between the first and second known positions of the target and receiver, respectively, and (a) one reflected from the reflector and received by the receiver. Or (b) identifying a transmitter position based on identifying a first angular difference between the reflected radar signals and (b) one or more orthogonal radar signals received directly by the receiver. A bistatic radar system that can include a transmitted transmitter location unit.

FIG. 2 shows a simplified schematic diagram of a bistatic radar system according to an embodiment of the present disclosure. FIG. 3 shows a simplified schematic diagram of a bistatic radar transmitter, according to an embodiment of the present disclosure. FIG. 2 shows a simplified schematic diagram of a bistatic radar receiver according to an embodiment of the present disclosure. FIG. 2 shows a simplified schematic diagram of a bistatic radar system according to an embodiment of the present disclosure. FIG. 2 shows a simplified schematic diagram of a bistatic radar system according to an embodiment of the present disclosure. FIG. 2 shows a simplified schematic diagram of a bistatic radar system according to an embodiment of the present disclosure. FIG. 2 shows a simplified schematic diagram of a bistatic radar system according to an embodiment of the present disclosure. FIG. 2 shows a simplified schematic diagram of a bistatic radar system according to an embodiment of the present disclosure. FIG. 2 shows a simplified schematic diagram of a bistatic radar system according to an embodiment of the present disclosure. FIG. 2 shows a simplified schematic diagram of a bistatic radar system according to an embodiment of the present disclosure. FIG. 2 shows a simplified schematic diagram of a bistatic radar system according to an embodiment of the present disclosure. 6 shows a flowchart of a method for locating a transmitter of a bistatic radar system according to an embodiment of the present disclosure.

  The foregoing summary, as well as the following detailed description of some embodiments, will be better understood when read with reference to the appended drawings, wherein: As used herein, an element or step described in the singular and followed by the word “a” or “an” may exclude the plural of the element or step. Unless explicitly stated, such exclusion should not be construed. Furthermore, references to “one embodiment” are not intended to be interpreted as excluding the existence of additional embodiments that also include the recited features. Further, unless expressly stated to the contrary, embodiments that “include” or “have” one or more elements with a particular property may include additional elements that do not have that property.

  Embodiments of the present disclosure provide a system and method for locating a transmitter of a bistatic radar system. The transmitter may stop communicating with the receiver. For example, the transmitter and receiver may not communicate position information with each other. Instead, the systems and methods of this disclosure are configured to determine the location or position of the transmitter by detecting radar signals transmitted by the transmitter.

  FIG. 1 shows a simplified schematic diagram of a bistatic radar system 100 according to an embodiment of the present disclosure. Bistatic radar system 100 includes a transmitter or illuminator 102 that is remote from receiver 104. The transmitter 102 and the receiver 104 may be separated by any distance that may or may not be a fixed distance. For example, one or both of transmitter 102 and receiver 104 may be mounted on a moving vehicle in the air, land, sea, or space. If desired, one or both of transmitter 102 and receiver 104 may be in a fixed location, such as in a building at a fixed location, such as on the ground or in the water.

  Bistatic radar system 100 also includes a target 106. Target 106 may be a moving or stationary object, vehicle, landmark, monument, terrain feature, and the like. As shown in FIG. 1, the target 106 may be an aircraft.

  The positions of the receiver 104 and the target 106 are known. For example, the receiver 104 is at a first known position 108, which may be land, sea or air, while the target 106 is a second known position that may be different from the first known position 108. 110. In contrast, the transmitter 102 is at an unknown location 112 at an initial stage, which may be land, sea or air.

  The location of receiver 104 and target 106 may be known by various systems and methods. For example, each of receiver 104 and target 106 may include a global positioning system (GPS) unit or device that identifies the respective location. In order for the target 106 to constantly communicate its location to the receiver 104, the receiver 104 and the target 106 may have a dedicated wireless link, voice communication link (eg, an individual at each location can call location data). May communicate with each other.

As shown, the transmitter 102, apart from the distance S ₁ only target 106 is an unknown distance in the first place. Target 106 are separated only from the receiver 104 a distance _{S 2} is a known distance. Receiver 104, are separated only from the transmitter 102 the distance S ₃ is an unknown distance in the first place. The angle between the S ₂ and _{S 3} are the theta _1. The angle between the S ₁ and _{S 3} are the theta _2. The angle between the S1 and the _{S 2} are the theta _3.

  In operation, the transmitter 102 transmits one or more radar signals 113 that may include a main beam 114 and side lobes 116. At least a portion of the main beam 114 and / or side lobe 116 is reflected from the target 106 and received by the receiver 104.

  FIG. 2 shows a simplified schematic diagram of a bistatic radar transmitter 118 according to an embodiment of the present disclosure. The transmitter 118 is an example of the transmitter 102 shown in FIG. The transmitter 118 may include a transmitter control unit 120 operably connected to a signal generator 122 such as an antenna, parabolic antenna (dish). The transmitter control unit 120 can be or include one or more processors, circuits, modules, etc. configured to control the operation of the transmitter 118. For example, the transmitter control unit 120 may control the radar signal transmitted from the signal generator 122.

  Transmitter 118 may transmit a pulse radar signal that may include main beam 114 and side lobe 116. For high pulse repetition frequency (PRF) radars, multiple coherent processing intervals (CPI) with different PRFs are used to eliminate range ambiguity using the Chinese Remainder Theorem or other such techniques. Can be used.

In at least one embodiment, the transmitter 102 (shown in FIG. 1) may include a signal generator 122 that may be a slowly rotating antenna (eg, a 10 second period) or a parabolic antenna. The signal generator 122 can rotate at a regular and predictable speed. Thus, the angle θ ₁ can be determined by identifying the time difference between receipt of the reflected radar signal from the target 106 and direct reception of the incident radar signal from the transmitter 102.

  FIG. 3 shows a simplified schematic diagram of a bistatic radar receiver 124 according to an embodiment of the present disclosure. The receiver 124 is an example of the receiver 104 shown in FIG. The receiver 104 may include a receiver control unit 126 operatively connected to a signal receiving structure 128 such as an antenna or a parabolic antenna. A signal receiving structure 128 may be directed to a known location 110 of the target 106. The receiver control unit 126 can be or include one or more processors, circuits, modules, etc. configured to control the operation of the receiver 124. For example, the receiver control unit 126 may analyze the radar signal received through the signal receiving structure 128. The signal receiving structure 128 may be fixed with respect to the platform or main housing of the receiver 124. The receive antenna beam of the signal receiving structure 128 can be steered electronically.

  The receiver 124 may also include a transmitter location unit 130 that may include one or more processors, circuits, modules, and the like. The transmitter location unit 130 may be part of the receiver control unit 126. If desired, the transmitter location unit 130 may be separate and independent from the receiver control unit 126. For example, transmitter location unit 130 may be housed in receiver 124 and communicate with receiver control unit 126. Alternatively, the transmitter location unit 130 may be separate and independent from the receiver 124. For example, the transmitter location unit 130 may be located at a separate location away from the receiver 124 and communicate with the receiver control unit 126. As described below, the transmitter location unit 130 is configured to receive one or more radar signals and identify the location of the transmitter 102.

  The receiver 104 (shown in FIG. 1) can include a signal receiving structure 128 that can be or include a directional or parabolic antenna directed toward the target 106. For example, the directional antenna of receiver 104 may include multiple beams or be scanned with a single beam.

  In at least one embodiment, transmitter location unit 130 determines the bistatic distance difference by measuring the time difference between receipt of an orthogonal pulse from radar sidelobe 116 and receipt of a reflected pulse from target 106. It can be specified. The transmitter location unit 130 may convert the time difference into a distance difference by multiplying the time difference by the speed of light.

  1 to 3, the transmitter position specifying unit 130 may specify the angle θ <b> 1 based on the radar signal received by the receiver 104. For example, the signal receiving structure 128 is directional to receive at least a portion of the main beam 114 or side lobe 116 reflected from the target 106 and at least a portion of the main beam 114 or side lobe 116 transmitted from the transmitter 102. It can be an antenna (such as a beamformer that is steered digitally).

A transmitter location unit 130 may analyze the received signal and identify a difference between the received angles of the received signal relative to the signal receiving structure 128. The two separate signals (e.g., at least a portion of the main beam 114 which is reflected from the target 106, at least a portion of the side lobe 116) the difference between the reception angle, provides the angle theta _1.

The positioning unit 130 is configured to determine the relative of the transmitter 102 to the receiver 104 by at least partially analyzing reflected radar signals from the target 106 (such as the reflected portion of the main beam 114 and / or the side lobe 116). The position can be specified. The location unit 130 may also analyze a direct or incident radar signal (such as a direct or incident portion of the main beam 114 and / or side lobe 116) transmitted from the transmitter 102. For example, the receiver 104 receives the reflected radar signal from the target 106 along the distance S ₂ is a known distance. The receiver 104 also receives direct or incident radar signal from transmitter 102 along a distance S _3. The location unit 130 analyzes the received reflected radar signal and the direct radar signal and identifies the angle θ _1, for example, through the analysis of the angle of reception by the antenna of the receiver 104 or the parabolic antenna as described above. After that, the position specifying unit 130 specifies the distance S ₃ and thus the position 112 based on the known distance S ₂ and the angle θ ₁ as described above.

A transmitter location unit 130 identifies the distance S ₂ by comparing the known location of the receiver 104 with the known location of the target 106. For example, the transmitter position identification unit 130, the known location 108 of receiver 104 by subtracting the known position 110 of the target 106, can identify the distance _{S 2.} Subsequently, the transmitter location identifying unit 130 identifies S ₃ and thus the location 113 of the transmitter 102 as described below.

Receiver 104 may receive a reflected radar signal from the target 106 to the first time T _1. The receiver 104 may also direct or incident signal from the transmitter 102 may receive a different second time T _2, the first time. The first time T ₁ may be a prior second time T _2, or vice versa. The reflected radar signal may include at least a portion of the main beam 114 reflected from the target 106. Alternatively, the reflected radar signal may include at least a portion of the side lobe 116 reflected from the target 106. Direct or incident signal may comprise at least part of the side lobe 116 to be sent directly from transmitter 102 along a straight line distance S _3. Alternatively, direct or incident signal may comprise at least a portion of the main beam 114 which is transmitted directly from transmitter 102 along a straight line distance S _3. The distances S ₁ , S ₂ and S ₃ are related to times T ₁ and T ₂ as follows.
S ₁ + S ₂ −S ₃ = C * (T ₁ −T ₂ ) (Equation 1)
Here, C is the speed of light.

The value K can be specified as follows:
K = S ₁ -S ₃ (Equation 2)

K can be specified as follows based on known or measured values for C, T ₁ , T ₂ and S ₂ .
K = C * (T ₁ −T ₂ ) −S ₂ (Equation 3)

As mentioned, the distance S ₂ is, since the distance between the known location 110 and 108 are known.

Then, the distance S ₃ are as follows, it can be identified.
S ₃ = (S ₂ ² −K ² ) / (2S ₂ cos θ ₁ + 2K) (Equation 4)

As described above, the transmitter location identifying unit 130 can identify the angle θ ₁ . Furthermore, the transmitter position identification unit 130, respectively on the basis of the known position 108 and 110 of the receiver 104 and the target 106, or otherwise identifies knowing the distance _{S 2.} By knowing the distance S ₂ and identifying the angle θ ₁ , the transmitter position identifying unit 130 can identify the distance S ₃ and thus the position 112.

Once the transmitter location unit 130 identifies the location 112 of the transmitter 102, the receiver control unit 126 may identify the location of all unknown target locations within the bistatic radar system 100. Accordingly, embodiments of the present disclosure provide systems and methods for locating transmitter 102 even when transmitter 102 is not in communication with receiver 104. By respectively know the position 108 and 110 of the receiver 104 and the target 106, the transmitter position identification unit 130 identifies the distance therebetween _{S 2.} Further, the receiver 104 may receive at least a portion of the main beam 114 (or side lobe 116) reflected from the target 106 and at least another portion of the main beam 114 and / or side lobe 116 directly from the transmitter 102. To determine the angle θ ₁ . Thereafter, the transmitter position specifying unit 130 specifies the distance S ₃ and thus the position 112 of the transmitter 102 based on the specification of S ₂ and the angle θ ₁ .

  The transmitter location unit 130 is configured to identify the location 112 of the transmitter 102 even when the receiver 104 and / or the target 106 is in communication with the transmitter 102. During such military missions or operations that communication between the transmitter 102 and the receiver 104 is not feasible and / or threatens the purpose, the bistatic radar system 100 does not communicate with the transmitter 102, Can work. For example, an enemy combatant may intercept communications on a communications link. Further, the bistatic radar system 100 can be used even when the transmitter 102 is non-cooperative with the receiver 104 (eg, refuses to transmit its position).

As stated, transmitter 102 may include a signal generator 122 that may be or include a rotating radar member such as an antenna or parabolic antenna. For a rotating radar member with a constant rotational speed, the radar rotational speed is measured, and the difference between the time when the main beam 114 is directed to the receiver 104 and the time when the reflected signal from the target 106 is received by the receiver 104 is calculated. By specifying, the angle θ ₂ can be specified. Thus, the additional identification of the angle θ ₂ can be used to check the specific accuracy of the position of the transmitter 102. For example, data regarding the rotational speed of the rotating radar member of the transmitter 102 can be supplied to the transmitter location unit 130. As an example, the rotating radar member can rotate through 360 degrees every 10 seconds. The transmitter location unit 130 also detects when the main beam 104 is directed to the receiver 104 and when the radar signal is received as a reflected signal from the target 106. Thus, thereafter, the transmitter position identification unit 130 may identify the angle theta _2. Thereafter, the transmitter position specifying unit 130 subtracts θ ₁ + θ ₂ from the angle θ ₁ known to the transmitter specifying unit 130, the angle θ ₂ specified by the transmitter specifying unit 130, and 180 degrees. Based on the angle θ ₃ that can be specified by the specifying unit 130, it can be determined whether the distances S ₁ , S ₂ , and S ₃ are matched. If the distances S ₁ , S ₂ and S ₃ coincide with a triangle having such an angle, the accuracy of the distance S ₃ can be confirmed. However, if the distances S ₁ , S ₂ , and S ₃ do not coincide with a triangle having such an angle, the transmitter location unit 130 determines that the distance S ₃ (and thus the identified position 112) is not. A warning message may be sent that may be accurate.

  Equations 1-4 above give a two-dimensional equation that is configured to identify a triangular geometry. However, equations 1 to 4 alone cannot specify the orientation of the triangle in the three-dimensional space. Two positions of the three vertices of the triangle can be identified hypothetically. The position of the third unknown vertex cannot be specified hypothetically. To determine the position of the third vertex, the height of the vertex relative to the receiver 104 can be known. The antenna of the receiver 104 can be used to determine the elevation angle.

FIG. 4 shows a simplified schematic diagram of a bistatic radar system 100 according to an embodiment of the present disclosure. In FIG. 4, the positions 108 and 110 of the receiver 104 and the target 106, respectively, may be known, while the position 112 of the transmitter 102 is unknown. The distances S ₁ , S ₂ , and S ₃ and the angles θ ₁ , θ ₂ , and θ ₃ can be identified as described above. In particular, the distances S ₁ , S ₂ , and S ₃ and the angles θ ₁ , θ ₂ , and θ ₃ are on the plane 200 defined by the positions 108, 110, and 112.

To determine the height of the transmitter 102 relative to the receiver 104, the transmitter location unit 130 can detect and identify the elevation angle Φ with the antenna of the receiver 104. Then, the height of the transmitter 102 relative to the receiver 104 can be specified as follows.
L ₃ = S ₃ sinΦ ₃ (Equation 5)
Here, L ₃ is the vertical distance from the horizontal plane H, the receiver 104 is facing towards the position 112, and S 3 is specified by Equation 3. Once the position 112 and height L _{3 of the} transmitter 102 are identified, such as by the transmitter localization unit 130 (shown in FIG. 3), the position of the unknown target is detected in three-dimensional space. Can be done.

FIG. 5 shows a simplified schematic diagram of a bistatic radar system 100 according to an embodiment of the present disclosure. As shown in FIG. 5, the position 108 and 112 are known (by, for example, by equation 1-3), the height _{L 2} of the target 106 might be unknown. To determine the height L ₂ of the target 106 relative to the receiver 104, the transmitter location unit 130 can detect and identify the elevation angle Φ with the antenna of the receiver 104. Then, the height or altitude of the target 106 relative to the receiver 104 can be specified as follows.
L ₂ = S ₂ sin Φ ₂ (Equation 6)
Here, L ₂ is the vertical distance from the horizontal plane H, the receiver 104 is facing towards the position 110, and, as mentioned above, S ₂ is known.

  With reference to FIGS. 1-5, the bistatic radar system 100 can constantly monitor the position of the receiver 104 and the target 106 and constantly update the location of the transmitter 102. For example, transmitter location unit 130 may update the location data for receiver 104 and target 106 once every X seconds to determine the location of transmitter 102. For example, position data regarding the receiver 104 and target 106 may be received by the transmitter location unit 130 every 5 seconds, and the transmitter location unit 130 transmits accordingly (eg, every 5 seconds). The position of the vessel 102 may be specified. However, it should be understood that the update period may be longer or shorter than 5 seconds. For example, if the bistatic radar system 100 is configured to detect the position of an aircraft moving at high speed, the bistatic radar system 100 is configured to detect the position of an aircraft moving at low speed. The update cycle may be shorter than the case.

  Any of transmitter 102, receiver 104, and target 106 may be fixed or movable. For example, transmitter 102, receiver 104, or target 106 may be located in an aircraft, land vehicle, ship, spacecraft, or the like.

  FIG. 6 shows a simplified schematic diagram of a bistatic radar system 200 according to an embodiment of the present disclosure. Bistatic radar system 200 may include a receiver 202 located in a fixed structure 204 located on the ground 206, such as a building. A transmitter 208 may be secured in a first vehicle 210, such as an aircraft. A second vehicle 212, such as a second aircraft, may be the target. The location of the transmitter 208 relative to the receiver 202 can be determined as described above. Alternatively, the first vehicle 210 and the second vehicle may be various other vehicles such as land vehicles or ships. Alternatively, the receiver 202 may be placed in a movable structure such as a vehicle, whether the vehicle is a land-based vehicle or a sky-based vehicle, It may be a vehicle based.

  FIG. 7 shows a simplified schematic diagram of a bistatic radar system 300 according to an embodiment of the present disclosure. Bistatic radar system 300 may include a receiver 302 located in a first vehicle 304, such as a first aircraft. A transmitter 308 may be secured in a second vehicle 310, such as a second aircraft. A third vehicle 312 such as a third aircraft may be the target. The location of the transmitter 308 relative to the receiver 302 can be determined as described above. Alternatively, the first vehicle 210 and the second vehicle may be various other vehicles such as land vehicles or ships.

  FIG. 8 shows a simplified schematic diagram of a bistatic radar system 400 according to an embodiment of the present disclosure. Bistatic radar system 400 may include a receiver 402 disposed in a first vehicle 404, such as a first land-based vehicle. The transmitter 308 can be placed in a fixed structure, such as, for example, fixed to the ground or suspended in water or on water. Alternatively, the transmitter 308 may be fixed in a vehicle such as an aircraft, land-based vehicle, or ship. A second vehicle 412 such as a second land based vehicle may be the target. The location of transmitter 408 relative to receiver 402 can be determined as described above.

  FIG. 9 shows a simplified schematic diagram of a bistatic radar system 500 according to an embodiment of the present disclosure. The bistatic radar system 500 may include a receiver 502 and a transmitter 504 that may be fixed or movable as described above. Geostationary satellites that orbit around the earth can serve as targets. The location of transmitter 504 relative to receiver 502 can be identified as described above.

  FIG. 10 shows a simplified schematic diagram of a bistatic radar system 600 according to an embodiment of the present disclosure. The bistatic radar system 600 may include a receiver 602 and a transmitter 604 that may be fixed or movable as described above. Receiver 602 and transmitter 604 may be located, for example, in the Earth's atmosphere or in outer space. The moon 606 or other celestial body can serve as a target. The location of transmitter 604 relative to receiver 602 can be identified as described above.

  FIG. 11 shows a simplified schematic diagram of a bistatic radar system 700 according to an embodiment of the present disclosure. Bistatic radar system 700 may include a receiver 702 in a ship 704 over water area 706. A transmitter 708 may travel in the sky, sea or land. A second vessel 710 on the water 706 can serve as the target. The location of transmitter 604 relative to receiver 602 can be identified as described above.

  FIG. 12 shows a flowchart of a method for locating a transmitter of a bistatic radar system according to an embodiment of the present disclosure. At 800, receiver location data indicating the location of the receiver is provided to a transmitter location unit that may be contained within the receiver or may be separate and independent of the receiver. At 802, target location data indicating the location of the auxiliary target is provided to the transmitter location unit.

  At 804, a transmitter location unit identifies a distance between the receiver location and the target location based on the received receiver location data and the target location data. For example, by knowing the position of the receiver and the target, the transmitter location unit can identify the distance between them, such as through subtraction.

  Next, at 806, the receiver receives one or more reflected radar signals (such as a portion of the main beam or sidelobe (s)) from the target. A transmitter location unit may analyze the reflected radar signal (s). At 808, a receiver receives one or more orthogonal or incident radar signals (such as sidelobe (s) or part of the main beam) from the transmitter.

  At 810, the transmitter location unit identifies an angular difference between the reflected radar signal (s) and the direct radar signal (s). For example, the transmitter location unit may detect and analyze the angle of reception of the signal by the receiver antenna and identify the difference therebetween. At 812, a transmitter location unit locates the transmitter relative to the receiver and target using the identified distance and angular difference between the receiver location and the target location.

  As described above, embodiments of the present disclosure provide a system and method for locating a transmitter of a bistatic radar system. A transmitter location unit may locate the transmitter relative to the receiver and target based on the known location of the receiver and target. Thus, the transmitter location may be unknown at an initial stage, but the transmitter location unit may determine the transmitter location by analyzing the receiver and target location data. The system and method may locate the transmitter without communicating with the transmitter.

  Embodiments of the present disclosure provide bistatic radar systems and methods that eliminate the need for expensive communication systems between transmitters and receivers.

  Furthermore, this disclosure includes embodiments that are in accordance with the following clauses.

Clause 1: a transmitter, a target at a first known location, and a receiver at a second known location, one or more reflected radars transmitted from the transmitter and reflected from the target Identifying a distance between a receiver configured to receive a signal and configured to receive one or more orthogonal radar signals transmitted from a transmitter and a first and second known position And configured to determine the location of the transmitter based on identifying a first angular difference between the one or more reflected radar signals and one or more orthogonal radar signals received by the receiver A bistatic radar system including a transmitter location unit.

Clause 2: The bistatic radar system of Clause 1, wherein the transmitter stops communicating with the transmitter location.

Clause 3: The bistatic radar system of clause 1, wherein the receiver includes a transmitter location unit.

Article 4: A first time (T ₁ ) at which one or more reflected radar signals or one or more orthogonal radar signals are received by the receiver, one or more reflected radar signals and one or more By measuring the time difference between a _second time (T ₂ ) at which the other of the direct radar signals of the receiver is received by the receiver, the transmitter locating unit is adapted to determine the bistatic distance difference. 1. The bistatic radar system of clause 1, wherein

Clause 5: The bistatic radar system of Clause 4, wherein the transmitter locating unit is configured to convert the time difference into a bistatic distance difference by multiplying the time difference by the speed of light.

Article 6: The transmitter is separated from the target by a _first linear distance (S ₁ ), the transmitter is separated from the receiver by a second linear distance (S ₂ ), and the receiver is a third linear distance (S ₃ ) away from the transmitter, and the transmitter location unit determines the first distance, the second distance, and the third distance as the first time and the second time, and S ₁ + S ₂ − The bistatic radar system of clause 4, wherein the bistatic radar system is configured to relate as follows: S ₃ = C * (T ₁ −T ₂ ), where C is the speed of light.

Clause 7: The bistatic radar system of Clause 6, wherein the transmitter location unit is configured to identify K = S ₁ -S ₃ , where K = C * (T ₁ -T ₂ ) -S ₂ .

Clause 8: The bistatic radar system of Clause 7, wherein the transmitter location unit is configured to identify the third distance as S ₃ = (S2 ² −K ² ) / (2S ₂ cos θ ₁ + 2K) .

Clause 9: The transmitter location unit is configured to determine a second angular difference between the main beam transmitted from the transmitter toward the target and the side lobe transmitted from the transmitter toward the receiver. The bistatic radar system of clause 1, wherein the transmitter location unit uses the second angular difference to identify the accuracy of the transmitter's particular location.

Clause 10: The clause of Clause 1, wherein the transmitter location unit is configured to identify one or both of a first height of the transmitter relative to the receiver and a second height of the target relative to the receiver Bistatic radar system.

Clause 11: The bistatic radar system of Clause 1, wherein each of the transmitter and target is moved or fixed in position.

Clause 12: providing target position data indicating a first position of the target to the transmitter locating unit, providing receiver position data indicating a second position of the receiver to the transmitter locating unit, transmission Receiving at the receiver one or more reflected radar signals transmitted from the transmitter and reflected from the target; receiving at the receiver one or more orthogonal radar signals transmitted from the transmitter; and Transmitted by the transmitter location unit based on the distance between the first position and the second position and the first angular difference between the one or more reflected radar signals and the one or more orthogonal radar signals. A bistatic radar method comprising identifying a third position of the device.

Clause 13: The bistatic radar method of Clause 12, further comprising stopping communicating third position data from the transmitter.

Clause 14: Locating the third position may include one or more reflected radar signals or a first time (T ₁ ) at which one or more orthogonal radar signals are received by the receiver and one or By measuring the time difference between a plurality of reflected radar signals and a second time (T ₂ ) at which one of the one or more orthogonal radar signals is received by the receiver, a bistatic distance difference is obtained. 12. The bistatic radar method of clause 12, comprising specifying.

Clause 15: The bistatic radar method of Clause 14, wherein identifying the third position further comprises converting the time difference to a bistatic distance difference by multiplying the time difference by the speed of light.

Article 16: The transmitter is separated from the target by a _first linear distance (S ₁ ), the transmitter is separated from the receiver by a second linear distance (S ₂ ), and the receiver is a third linear distance (S ₃ ) away from the transmitter and identifying the third position is the first distance, the second distance, and the third distance, the first time and the second time, and S ₁ The bistatic radar method of clause 14, further comprising: + S ₂ −S ₃ = C * (T ₁ −T ₂ ), where C is the speed of light.

Article 17: Identifying a third position
Specify K = S ₁ -S ₃ as K = C * (T ₁ −T ₂ ) −S ₂ and specify S ₃ = (S ₂ ² −K ² ) / (2S ₂ cos θ ₁ + 2K) The bistatic radar method of clause 16, further comprising:

Clause 18: Identify a second angular difference between the main beam transmitted from the transmitter towards the target and the side lobe transmitted from the transmitter towards the receiver, and using the second angular difference, 13. The bistatic radar method of clause 12, further comprising determining the accuracy of the specific location of the transmitter.

Clause 19: The bistatic radar method of Clause 12, further comprising identifying one or both of a first height of the transmitter relative to the receiver and a second height of the target relative to the receiver.

Article 20: Identifying the distance between the first and second known positions of the target and receiver, respectively, and (a) one or more reflected radar signals reflected from the reflector and received by the receiver (B) a transmitter location unit configured to locate a transmitter based on identifying a first angular difference between one or more orthogonal radar signals received directly by the receiver; Including bistatic radar system.

  As used herein, the terms “computer”, “control unit” or “module” refer to a microcontroller, reduced instruction set computer (RISC), application specific integrated circuit (ASIC), logic circuit, and the present specification. Any processor-based or microprocessor-based system may be included, including systems using any other circuit or processor capable of performing the functions described in the document. The above examples are exemplary only, and are therefore not intended to limit in any way the definition and / or meaning of the terms “computer”, “control unit” or “module”.

  A computer, control unit, or processor executes a set of instructions that are stored in one or more storage elements, in order to process data. The storage element may also store data or other information as desired or required. The storage element may be in the form of an information source or a physical memory element within the processor.

  The set of instructions may include various commands that instruct a computer, control unit, or processor as a processor to perform certain operations, such as the methods and processes of the various embodiments of the subject matter described herein. The set of instructions can be in the form of a software program. The software can be in various forms such as system software or application software. Furthermore, the software may be in the form of a collection of individual programs or modules, a program module within a larger program, or a portion of a program module. The software may also include modular programming in the form of object oriented programming. The processing of input data by the processor may be in response to a user command, in response to a result of a previous process, or in response to a request made by another processor.

  The illustrations of the embodiments herein may show one or more control units or modules. A control unit or module, along with associated instructions (e.g., software stored on a tangible and fixed computer-readable storage medium, such as a computer hard drive, ROM, RAM, etc.) that performs the operations described herein. It should be understood that it represents one or more circuits, one or more circuit modules, etc. that may be implemented as hardware. The hardware may include state machine circuits that are physically wired to perform the functions described herein. If desired, the hardware may include electronic circuitry that includes and / or is connected to one or more logic-based devices, such as a microprocessor, processor, controller, and the like. If desired, the module may include processing circuitry such as one or more field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), microprocessor (s), quantum computing devices, and / or the like. May be represented. Circuit modules in various embodiments may be configured to execute one or more algorithms that perform the functions described herein. One or more algorithms may include aspects of the embodiments disclosed herein, whether explicitly identified in a flowchart or method.

  As used herein, the terms “software” and “firmware” are interchangeable and include computer-implemented execution, including RAM memory, ROM memory, EPROM memory, EEPROM memory, and non-volatile RAM (NVRAM) memory. Including any computer program stored in a memory for. The above memory types are exemplary only, and thus do not limit the types of memory that can be used to store computer programs.

  Various spatial and directional terms such as top, bottom, lower, central, lateral, horizontal, vertical, front, etc. may be used to describe embodiments of the present disclosure. However, it is understood that such terms are only used with respect to the orientation shown in the drawings. The orientation may be reversed, rotated, or otherwise changed, such that the top is the bottom and vice versa, the horizontal is vertical, and so on.

  As used herein, a structure, limit, or element that is “configured” to perform a task or task is specifically structured, constructed, or adapted in a manner that corresponds to that task or task. . For purposes of clarity and avoidance of doubt, an object that simply has the ability to be modified to perform a task or task, as used herein, is “configured” to perform the task or task. Not.

  The above-described embodiments (and / or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the inventive subject matter without departing from the scope of the inventive subject matter. Although the dimensions and types of materials described herein are intended to define the parameters of the present inventive subject matter, they are illustrative rather than limiting. Many other embodiments will be apparent to those of skill in the art upon reviewing this description. Therefore, the scope of the inventive subject matter should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” refer to the plain English terms of “comprising” and “where”, respectively. Used as a synonym. Further, in the following claims, terms such as “first”, “second” and “third” are merely used as labels and are intended to impose numerical requirements on their objects. is not. Further, the following claims limitations are not described in means-plus-function format, and such claims are limited by means of “an additional unstructured function description”. Unless the phrase “means for” is expressly used, it is not intended to be construed under 35 USC 112 (f).

  This written description is intended to disclose some embodiments of the present subject matter and to enable any person skilled in the art to make and use any device or system and any method incorporated. An example is used so that embodiments of the present inventive subject matter can be implemented, including performing The patentable scope of the inventive subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples include when they have structural elements that do not differ from the language of the claims, or when they include equivalent structural elements that do not differ substantially from the language of the claims, It is intended to be within the scope of the claims.

Claims (10)

A transmitter (102);
A target (106) in a first known position (110);
A receiver (104) at a second known location (108), configured to receive one or more reflected radar signals (113) transmitted from the transmitter and reflected from the target A receiver configured to receive one or more direct radar signals (113) transmitted from the transmitter;
Identifying a distance between the first and second known positions and a first between the one or more reflected radar signals and the one or more orthogonal radar signals received by the receiver. A bi-static radar system comprising: a transmitter location unit (130) configured to identify the transmitter location (112) based on the identification of the angular difference of the transmitter.   The bistatic radar system of claim 1, wherein the transmitter stops communicating the location of the transmitter.   The bistatic radar system according to claim 1 or 2, wherein the receiver includes the transmitter location unit. A first time (T ₁ ) at which the one or more reflected radar signals or the one or more orthogonal radar signals are received by a receiver, the one or more reflected radar signals and the one or more By measuring the time difference between a _second time (T ₂ ) at which the other of the plurality of direct radar signals is received by the receiver, the transmitter location unit determines the bistatic distance difference The bistatic radar system according to any one of claims 1 to 3, wherein the bistatic radar system is configured to.   The transmitter localization unit determines a second angular difference between a main beam transmitted from the transmitter towards the target and a sidelobe transmitted from the transmitter towards the receiver; The transmitter location unit is configured to determine the accuracy of the location of the identified transmitter using the second angular difference. Bistatic radar system.   The transmitter locating unit is configured to identify one or both of a first height of the transmitter relative to the receiver and a second height of the target relative to the receiver. Item 6. The bistatic radar system according to any one of Items 1 to 5.   The bistatic radar system according to any one of claims 1 to 6, wherein each of the transmitter and the target is moved or fixed in position. Providing target location data indicative of the first location (110) of the target (106) to the transmitter location unit (130);
Providing receiver location data indicative of a second location (108) of the receiver (104) to the transmitter location unit;
Receiving at the receiver one or more reflected radar signals (113) transmitted from the transmitter (112) and reflected from the target;
Receiving at the receiver one or more orthogonal radar signals (113) transmitted from the transmitter; and the distance between the first position and the second position and the one or more Identifying a third position (112) of the transmitter at the transmitter location unit based on a first angular difference between a reflected radar signal and the one or more orthogonal radar signals. Static radar method.   The bistatic radar method of claim 8, further comprising stopping communicating the third position data from the transmitter.   10. The bistatic of claim 8 or 9, further comprising identifying one or both of a first height of the transmitter relative to the receiver and a second height of the target relative to the receiver. Radar method.

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